smoking at idle

[twinturbosedan]

i'm trying to figure out why my car is smoking a bit at idle.  the only time it smokes is when i come to a stoplight or the car is just sitting at idle...after a few moments it will start to smoke white smoke.  sometimes i'll be delivering a pizza and leave the car running out in front, and then when i go back out to my car i can see some smoke coming out.  sometimes when i take off it will leave a fairly large white cloud but then it stops smoking altogether.  it doesn't smoke at all while i'm driving or at WOT etc....only after idling for a minute or two after the engine is fully warmed up.

well today i finally got around to replacing the turbo oil return hose.  i got a new hose from ATP Turbo.  the old one was definately bad...it was blistered all the way down the length of the hose :oops: .  although it still looked like oil could drain through it no problem...

so anyways that did not seem to help at all.  it's still doing it.  any ideas?  the heads were rebuilt with new valve seals last summer so i don't think that's it.  engine has really good oil pressure despite having ~240,000 miles (new Melling 95HV oil pump installed last summer).  engine oil stays very clean.  i haven't changed the oil (Mobil-1 10w30) since late last October and it still looks light golden-brown.  it doesn't leak oil but i do have to add oil due to it burning off.  turbo has practically zero shaft play and there is no oil in the intercooler pipes.

i'm going to be checking spark plugs tomarrow....any ideas appreciated thanks

[TGPilot]

Have you pulled your intercooler to see if you have puddling at the bottom? 8)

[Invasion1]

White smoke is coolant and its most likely the water seal in the turbo...
:(

One of the TGP engines i sold to a Cav kid was apparently doing the same thing but 10 fold worse than what you describe.

Skalor mentioned a replacement awhile back

this:

http://cgi.ebay.com/ebaymotors/T2-T25-T28-Turbo-Stagger-Gap-Turbine-Shaft-Seal_W0QQitemZ8043598512QQcategoryZ33742QQrdZ1QQcmdZViewItem

Upgrade from the stock one.

here is the post on w-body.com

http://www.w-body.com/forum/viewtopic.php?t=32745&highlight=seal

[twinturbosedan]

Have you pulled your intercooler to see if you have puddling at the bottom? 8)

i haven't actually pulled the intercooler but when i was putting the new silicone couplers & T-bolt clamps in last week i did not see any oil at the bottom of the intercooler.  both the upper and lower pipes were also clean/dry inside.

[twinturbosedan]

White smoke is coolant and its most likely the water seal in the turbo...
:(

One of the TGP engines i sold to a Cav kid was apparently doing the same thing but 10 fold worse than what you describe.

Skalor mentioned a replacement awhile back

this:

http://cgi.ebay.com/ebaymotors/T2-T25-T28-Turbo-Stagger-Gap-Turbine-Shaft-Seal_W0QQitemZ8043598512QQcategoryZ33742QQrdZ1QQcmdZViewItem

Upgrade from the stock one.

here is the post on w-body.com

http://www.w-body.com/forum/viewtopic.php?t=32745&highlight=seal

yeah it's really not smoking that bad.  i have another good TGP turbo sitting here - maybe i'll swap it out tomarrow.  i do have another bad TGP turbo here (lots of shaft play) but i don't trust my ability to take them apart and rebuild them :lol:

fwiw, the smoke doesn't smell like coolant at all...it smells like oil...it smells alot like how an old cylinder head bolt stinks right after removing it.

[TGPilot]

Oh sorry didn't see the color of the smoke. 99% of the time White is water as Dave said.

You might want to pull your plugs to see if you have crust growing on your electrodes.

Dave...I do not know the design of the T-25 turbo cooling/oiling cartridge. Which side is it prone to leak into intake or exhaust? 8)

[twinturbosedan]

here is the post on w-body.com

http://www.w-body.com/forum/viewtopic.php?t=32745&highlight=seal

oh yeah...i noticed i posted in that thread.  that was right after i had the turbo project completed.  it's wierd...the problem completey went away and now it's back.  although, last August it seemed like it only happened a couple times and when it did happen it smoked alot more than it does now.  last August i also noticed oil seeping from between the turbo and downpipe...so much so that some even started dripping on top of the tranny.  i looked for signs of oil seeping out from between the turbo and downpipe today and didn't see any; it was dry.

i have tomarrow off work, i think i might just swap the turbo out for something to do and see what happens.

[Invasion1]

From my readings (done alot to find out my oil leaking into the DP issue) the intake side is almost builtproof....its the exhaust side thats a problem for coolant and oil, oil seal is more forgiving than coolant/water though.

[twinturbosedan]

Oh sorry didn't see the color of the smoke. 99% of the time White is water as Dave said.

last August when it was burning oil out the downpipe the smoke was white just like it is now...IIRC it even smelled the same.  i'm certain it was oil burning (last August anyway) since there was oil leaking out from between the turbo and downpipe.

definately checking plugs tomarrow.  thanks guys.

[Prospeeder]

Well i also had white smoke, and the oil return line solved it. BUT extended periods of a blocked oil return will cause permenate oil seal failure on the turbine side from what iv read. Also it may seem like the oil would flow through fine, but when the oil gets hot, those blisters will swell up and block flow quite abit! If oil is seeping out the down pipe as you said, i think youve found your problem! Cheapturbo.com has rebuilds for 300$ and alot of people reccomend them, good luck!

[TGPilot]

The following question is not me being a smartass!

So white can be from oil? It must be from post cumbustion chamber then...like how deisel will for a white clouod before it bursts into flames when it is heated??

Seriously not beign a smartass...I am wanting to learn here! :wink:  8)

[TurboGTU]

Was it smoking before or after the Mobil 1?

Because like said...bad oil return lines can cause oil to back up and basicly stall on the seals. The turbine side will cook and carbonise. When I rebuilt my turbos, I've alsways find carbon under the turbine ring seal.  This carbon can push the ring seal hard agains the case or tries to push itself agains the turbine shaft jurnal. WHen I remove them..there's significant weare on the turbine side face of the ring and scaring on the housing mating surface of the ring.
Good thing mine only needed a new ring only. Worse case you'll need to hone the ring jurnal on the housing to rid of the indention.
If it has no free play, I would just buy the turbine seal. Someone on ebay by the name of turbopimp had them. I would get the gapless seal.

Oh..the reason I said if it smoked before or after the oil change was because if it had regular oil, it would keep the carbon buildup there. WHen you changed to the syn oil, the oil would "clean" out and seap out though the carbon buildup and loose clearances. Kinda like worn motors switching to synthetic and then started leaking though the main seals.. :lol: . That sluge holds the regular oil in.  :?

[twinturbosedan]

both actually.

last August (right after i turbocharged the engine) i started out using conventional Valvoline 10w30.  i switched to Mobil-1 10w30 in October.  it's been doing the smoking thing for the past couple weeks and i just figured it was the oil return hose.  it really doesn't smoke too badly but enough to be a little annoying.

i'm not 100% positive it's the same problem as i was having last August (though it DOES seem that way to me).  last August the problem was obvious because i could see the oil leaking out from between the turbo and downpipe.  i haven't seen any oil seeping out this time around but then again it isn't smoking as bad as it was in August either.

[TGPRobNY]

There is usually too much oil pressure going into the turbo in the first place. Billowing clouds of mosquito killing smoke then sometimes it disappears. Pulling plugs show no evidence of oil and it lays in the exhaust system and it will eventually burn off once you put a restrictor in. Good luck